摘要：The air temperature is the main climatic parameter which gives important information about climate change and variability. The increasing of the temperature and frequency of occurrence of extreme high temperatures during the recent years is one of the features of climate which is associated with the global climate change. The present study aims to analyze the variability of air temperatures in the mountainous area of Bulgaria and in Rila Mountain in particular by the investigation of chronological distribution of extreme cold and extreme warm months. Extreme temperature months are determined according to 10-th and 90-th percentiles of the distribution of monthly data. On the basis of the investigation of extreme temperature months during the period 1960-2012 the increase of warm and decrease of cold months are determined at annual level and also for summer-time and winter-time. The results show that the warming during the summer-time (May-October) is more clearly established that in winter-time (November-April).
关键词：extreme temperature months; threshold of 10-th and 90-th percentile; Rila Mountain
